Prior to connecting a user device, such as a computer, a personal digital assistant (PDA), or the like to a network device, such as a network server, an email server, a network printer, etc., on a secure network, the user device, or the user employing the user device, generally must be authenticated on the network and/or authorized to access the particular network device. In order to be authenticated, the user or user device will generally send an authentication request to a Network Access Server (NAS). A user may send an authentication request by interfacing with an interactive software mechanism such as a VPN client, an email program, a web page, etc. Alternatively, a user device may transmit an authentication request independently of user intervention, such as by transmitting a request directly using a specified authentication protocol. The NAS may be, for example, a Secure Socket Layer (SSL) based remote access system, a Virtual Private Network (VPN) switch, a firewall switch, a Secure Shell (SSH) based remote access gateway, an Internet Protocol (IP) router, or a modem bank. The NAS may be in selective communication with an authentication server. Generally speaking, an authentication server is a device that receives an authentication request from a NAS and returns a response indicating whether the user device is to be granted access to a requested network or network device, what level of service is allowed on the network or network device, and/or whether a user is properly authenticated. The response may include additional information as well, which may be used by the NAS to determine parameters governing the access provided to the user device.
Traditional authentication servers are generally configured to monitor a single port, and to thereby receive authentication requests communicated using a single authentication protocol. Accordingly, for an authentication system to respond to authentication requests transmitted using more than one authentication protocol, the system may require at least one authentication server for each authentication protocol. Further, some authentication servers may be configured to perform authentication, or authorization, but not both, which may further increase the number of authentication servers required in an authentication system.